We describe a novel approach for building a secure and fault tolerant data
storage service in collaborative work environments.
In such environments, sensitive data must be accessible only to a select group
of people, whose membership may change over time. Key management issues
are a recognized problem in such environments. We eliminate this problem for
confidential and secure data storage by using perfect secret sharing techniques
for storing data. Perfect secret sharing schemes have found little use in
managing generic data because of the high computation overheads incurred by
existing schemes. Our proposed approach uses a novel combination of XOR secret
sharing and replication mechanisms, which drastically reduce the computation
overheads and achieve speeds comparable to standard encryption schemes. The
combination of secret sharing and replication manifests itself as an
architectural framework, which has the attractive property that its dimension
can be varied to tradeoff amongst different performance metrics. We evaluate
the properties and performance of the proposed framework to show that the
combination of perfect secret sharing and replication can be used to build
efficient fault-tolerant and secure distributed data storage systems for collaborative work environments.